Download BIOL241articulations8JUL2012

11/07/12 Articulations
BIOL241 – “Lecture 8”
Overview
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Joint classifications: structural and functional
Types of joints by functional classification
Synovial joint detail
Movements at synovial joints
Classification of synovial joints by shape
Examples of joints
Injuries
Arthritis
Articulations
•  Body movement occurs at joints
(articulations) where 2 bones connect
•  Weakest parts of the skeleton
•  Articulation – site where two or more
bones meet
•  Functions of joints
–  Give the skeleton mobility
–  Hold the skeleton together
1 11/07/12 Joint Structure
•  Determines direction and distance of
movement (range of motion)
•  Joint strength decreases as mobility
increases
Classification of Joints: Structural
•  Structural classification focuses on the
material binding bones together and
whether or not a joint cavity is present
•  The three structural classifications are:
–  Fibrous
–  Cartilaginous
–  Synovial
Structural Classification
Table 9–2
2 11/07/12 Structural Classifica3ons • 
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Bony (fused) Fibrous (collagen fibers) Car3laginous (car3lage) Synovial (synovial fluid) Classifica3on of Joints: Func3onal •  Func3onal classifica3on is based on the amount of movement allowed by the joint •  The three func3onal classes of joints are: –  Synarthroses – immovable –  Amphiarthroses – slightly movable –  Diarthroses – freely movable Func3onal Classifica3on Table 9–1
3 11/07/12 Synarthroses • 
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Also called immovable joints Are very strong Edges of bones may touch or interlock Fibrous, bony, or car3laginous connec3ons May fuse over 3me Four types: –  Suture –  Gomphosis –  Synchondrosis –  Synostosis Synarthroses 1 of 2 •  Suture –  Bones are interlocked –  Bound by dense fibrous connec3ve 3ssue –  Found only in skull •  Gomphosis –  Fibrous connec3on (periodontal ligament) –  Binds teeth to sockets Synarthrosis: Suture Figure 8.1a 4 11/07/12 Synarthroses 2 of 2 •  Synchondrosis –  A rigid car3laginous bridge between 2 bones: •  epiphyseal car3lage of long bones •  between vertebrosternal ribs and sternum •  Synostosis –  Fused bones, immovable: •  metopic suture of skull •  epiphyseal lines of long bones Synarthrosis: Synchondroses Figure 8.2a, b Amphiarthroses •  Also called slightly moveable joints •  Can be fibrous or car3laginous connec3ons Func3onally: •  More moveable than synarthrosis •  Stronger than freely movable joint •  Types: –  Syndesmosis –  Symphysis 5 11/07/12 2 Types of Amphiarthroses •  Syndesmosis: –  bones connected by ligaments –  e.g. between 3bia and fibula •  Symphysis: –  bones separated by fibrocar3lage –  Examples? Amphiarthrosis (Fibrous) : Syndesmoses Figure 8.1b Amphiarthrosis (Car3laginous): Symphyses Figure 8.2c 6 11/07/12 Diarthroses Synovial joints Also called freely moveable joints At ends of long bones Found within ar3cular capsules (con3nuous with periosteum) lined with synovial membrane and filled with fluid •  Include all limb joints and many others •  Subdivided by the type of mo3on each can undergo • 
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Synovial Joints: General Structure •  Synovial joints all have the following –  Ar3cular car3lage –  Joint (synovial) cavity –  Ar3cular capsule –  Synovial fluid –  Reinforcing ligaments Synovial Joints: General Structure Figure 8.3a, b 7 11/07/12 Synovial membrane •  Has incomplete epithelium •  Areolar 3ssue underneath has rich blood supply •  Creates synovial fluid and proteoglycans (from fibroblasts) to make it viscous •  No blood supply enters the joint itself Fric3on Reduc3on Ar2cular car2lage: pads ar3cula3ng surfaces within ar3cular capsules to prevent bones from touching •  Synovial fluid lubricates the smooth surfaces, con3ans proteoglycans secreted by fibroblasts (from where?) Func9ons: • 
1.  Lubrica3on 2.  Shock absorp3on 3.  Nutrient distribu3on – from areloalar 3ssue of synovial membrane to the ar3cular car3lage and fibrocar3lage pads Synovial Joints: Fric3on-­‐Reducing Structures Figure 8.4 8 11/07/12 Synovial Joints: Stability •  Stabilizing Factors -­‐ prevent injury by limi3ng range of mo3on: –  Ar3cular surfaces – shape determines what movements are possible –  Ligaments – unite bones and prevent excessive or undesirable mo3on –  Muscle tendons across joints ac3ng as stabilizing factors, are kept 3ght at all 3mes by muscle tone Accessory structures Part 1 •  Car3lages: Cushion the joint –  Ar3cular hyaline car3lage –  fibrocar3lage meniscus (ar9cular disc) •  Bursa: Cushion areas where ligaments, muscles, skin, tendons, or bones rub together –  flabened, fibrous sacs lined with synovial membranes and containing synovial fluid –  Tendon sheath: elongated bursa that wraps completely around a tendon Accessory structures Part 2 •  Fat Pads: Protect ar3cular car3lages –  Superficial (overlying) to the joint capsule •  Accessory Ligaments: Support, strengthen joints •  Tendons: Abach to muscles around joint to help support it 9 11/07/12 Synovial Joints: Movement •  The two muscle abachments across a joint are: –  Origin – abachment to the immovable bone –  Inser3on – abachment to the movable bone •  Described as movement along transverse (horizontal), frontal, or sagibal planes Basic types of dynamic mo3on •  Linear mo3on (gliding) •  Angular mo3on •  Rota3on Linear Mo3on •  One flat bone surface glides or slips over another similar surface •  Examples – intercarpal and intertarsal joints, and between the flat ar3cular processes of the vertebrae Pencil maintains ver3cal orienta3on, but changes posi3on Figure 9–2a, b
10 11/07/12 Angular Mo3on •  Pencil maintains posi3on, but changes orienta3on –  Tip stays fixed; pencil does not rotate •  Many examples Figure 9–2c
Angular Mo3on •  Flexion — bending movement that decreases the angle of the joint •  Extension — reverse of flexion; joint angle is increased •  Dorsiflexion and plantar flexion — up and down movement of the foot •  Abduc3on — movement away from the midline •  Adduc3on — movement toward the midline •  Circumduc3on — movement describes a cone in space Angular Mo3on: Circumduc3on •  Angular mo3on in a circle –  Again, 3p does not rotate Figure 9–2d
11 11/07/12 Rota3on •  NOT angular •  Pencil maintains posi3on and orienta3on, but spins •  Example – shaking your head Figure 9–2e
Synovial Joints: Range of Mo3on • 
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Nonaxial – slipping movements only Monaxial/Uniaxial – movement in one plane Biaxial – movement in two planes Triaxial – movement in or around all three planes Types of Movements at Synovial Joints •  Terms describe: –  plane or direc3on of mo3on –  rela3onship between structures •  In the anatomical posi3on, all joints except one are at full extension 12 11/07/12 Gliding Movement Figure 8.5a Flexion/Extension •  Angular mo3on in the Anterior–posterior plane •  Flexion reduces angle between elements •  Extension increases angle between elements Angular Movement – F/E Figure 8.5b 13 11/07/12 Hyperextension •  Angular mo3on •  Extension past anatomical posi3on Angular Movement -­‐ Hyperextension Figure 8.5c, d Dorsiflexion and Plantar Flexion •  Dorsiflexion: –  flexion at ankle (liging toes) –  Is “true flexion” •  Plantar flexion: –  extension at ankle (poin3ng toes) 14 11/07/12 Abduc3on and Adduc3on •  Both are Angular mo3on in the Frontal plane •  Abduc3on moves away from longitudinal axis •  Adduc3on moves toward longitudinal axis Angular Movements -­‐ Ab/Ad/Circum Figure 8.5e, f Circumduc3on •  Angular mo3on in a circle without rota3on 15 11/07/12 Rota3on •  The turning of a bone around its own long axis •  Leg or right rota3on •  Medial rota3on (inward rota9on): –  rotates toward axis •  Lateral rota3on (outward rota9on): –  rotates away from axis •  Examples –  Between first two vertebrae –  Hip and shoulder joints Figure 8.5g Special Movements • 
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Supina3on and prona3on Inversion and eversion Protrac3on and retrac3on Eleva3on and depression Opposi3on Special Movements Figure 8.6a 16 11/07/12 Special Movements Figure 8.6b Special Movements Figure 8.6c Special Movements Figure 8.6d 17 11/07/12 Special Movements Figure 8.6e Lateral Flexion •  Bends vertebral column from side to side Figure 9–5f
MOVIE •  Angular mo3ons 18 11/07/12 Classifica3on of Synovial Joints by Shape • 
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Gliding/Plane Hinge Pivot Ellipsoidal Saddle Ball-­‐and-­‐socket Gliding Joints • 
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Flabened or slightly curved faces Limited mo3on (only examples of nonaxial) Also called linear mo3on 2 surfaces slide past each other: –  between carpal or tarsal bones Figure 9–6 (1 of 6)
19 11/07/12 Hinge Joints •  Cylindrical projec3ons of one bone fits into a trough-­‐shaped surface on another •  Angular mo3on in a single plane (monaxial) •  Flexion/extension only •  Elbow, knee Figure 9–6 (2 of 6)
Pivot Joints •  Rounded end of one bone protrudes into a “sleeve,” or ring, composed of bone (and possibly ligaments) of another •  Rota3on only (monaxial) •  Shaking your head Figure 9–6 (3 of 6)
Ellipsoidal Joints •  Oval ar3cular face within a depression •  Mo3on in 2 planes (biaxial) •  Some wrist joints (e.g. radiocarpal) Figure 9–6 (4 of 6)
20 11/07/12 Saddle Joints •  2 concave faces, straddled (biaxial) •  Thumb (carpometacarpal) Figure 9–6 (5 of 6)
Ball-­‐and-­‐Socket Joints •  A spherical or hemispherical ar3cular face head of one bone ar3culates with a cuplike socket of another (triaxial) •  Shoulder, hip Figure 9–6 (6 of 6)
MOVIE •  Types of synovial joint mo3on 21 11/07/12 Specific joint examples Vertebrae, shoulder, elbow, hip, knee IMPORTANT •  You DO NOT need to know the names of specific ligaments in the examples that follow. Only learn the general concepts about these joints (and the terms listed in blue). •  You DO need to know what type of joint is found at any site in the body Intervertebral Ar3cula3ons Figure 9–7
22 11/07/12 Intervertebral Ar3cula3ons •  C2 to L5 spinal vertebrae ar3culate in two places: –  at inferior and superior ar3cular processes •  gliding synovial joints –  between adjacent vertebral bodies •  symphyseal joints (symphysis = fibroca3lage pad) •  The atlas and axis have a pivot joint (monaxial synovial) Intervertebral Discs •  Intervertebral discs: –  pads of fibrocar3lage that separate vertebral bodies •  Slipped (bulging) disc: –  bulge in outer anulus fibrosus of disc –  invades vertebral canal, may press on nerves or cord •  Herniated disc: –  Inner, gela3nous nucleus pulposus breaks through anulus fibrosus –  presses on spinal cord or nerves Damage to Intervertebral Discs Figure 9–8
23 11/07/12 Movements of the Vertebral Column •  Flexion/Extension –  bends anteriorly and posteriorly –  Caused by small gliding movements of adjacent vertebrae •  Lateral flexion: –  bends laterally •  Rota3on Temporomandibular Joint (TMJ) •  Mandibular condyle ar3culate with the temporal bone •  Two types of movement –  Hinge – depression and eleva3on of mandible –  Side to side – (lateral excursion) grinding of teeth Temporomandibular Joint Figure 8.13a, b 24 11/07/12 Ac3vity •  Get in small groups •  Compare and contrast the shoulder, hip, and knee joints on the basis of: – Range of mo3on – Stability/Protec3on – Injury frequency The Shoulder Joint Figure 9–9a
The Shoulder Joint •  Also called the glenohumeral joint: •  Ball-­‐and-­‐socket triaxial diarthrosis in which stability is sacrificed to obtain greater freedom of movement •  Head of humerus ar3culates with the glenoid fossa of the scapula •  Allows more mo3on than any other joint •  Is the least stable •  Supported by skeletal muscles, tendons, ligaments 25 11/07/12 Shoulder Stability •  Weak stability is maintained by: –  Thin, loose joint capsule –  Four ligaments – coracohumeral, and three glenohumeral –  Tendon of the long head of biceps, which travels through the intertubercular groove and secures the humerus to the glenoid cavity –  Rotator cuff (four tendons) that encircles the shoulder joint and blends with the ar3cular capsule Shoulder Stability Figure 8.11a Socket of the Shoulder Joint •  Glenoid labrum: –  deepens socket of glenoid cavity –  fibrocar3lage lining –  extends past the bone 26 11/07/12 Processes of the Shoulder Joint •  Acromion (clavicle) and coracoid process (scapula): –  project laterally, superior to the humerus –  help stabilize the joint •  Shoulder Separa3on –  Par3al or complete disloca3on of Acromioclavicular joint Shoulder Muscles (FYI) •  Also called rotator cuff: –  supraspinatus –  infraspinatus –  subscapularis –  teres minor The Hip Joint Figure 9–11a
27 11/07/12 Hip (Coxal) Joint •  Ball-­‐and-­‐socket triaxial diarthrosis •  Head of the femur ar3culates with the acetabulum •  Socket of acetabulum is extended (made larger) by fibrocar3lage acetabular labrum •  Good range of mo3on, but limited by the deep socket and strong ligaments •  Stronger than shoulder, but more limited range of mo3on Hip Stability Acetabular labrum Iliofemoral ligament Pubofemoral ligament Ischiofemoral ligament •  Ligamentum teres • 
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Figure 8.12a Hip Stability Figure 8.12c, d 28 11/07/12 The Knee Joint Figure 9–12a, b
The Knee Joint Figure 9–12c, d
The Knee Joint • 
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A complicated hinge joint Largest and most complex joint of the body Allows flexion, extension, and limited rota3on Three joints in one surrounded by a single joint cavity –  Femoropatellar joint –  Lateral and medial 3biofemoral joints (at medial and lateral condyles) •  Transfers weight from femur to 3bia 29 11/07/12 Menisci of the Knee •  Medial and lateral menisci: –  fibrocar3lage pads –  one at each femur–3bia ar3cula3on –  cushion and stabilize joint –  give lateral support •  Standing with legs straight “locks” knees by jamming lateral meniscus between 3bia and femur which may interrupt venous return from lower leg FYI: 7 Ligaments of the Knee Joint •  Patellar ligament (anterior) •  2 popliteal ligaments (posterior) •  Anterior and posterior cruciate ligaments (inside joint capsule) •  Tibial collateral ligament (medial) •  Fibular collateral ligament (lateral) Knee Ligaments and Tendons – Anterior surface •  Tendon of the quadriceps femoris muscle •  Patellar ligament •  Lateral and medial patellar re3nacula •  Fibular and 3bial collateral ligaments Figure 8.8c 30 11/07/12 Knee – Interior Suppor3ng Structures •  All inside the joint capsule: –  Anterior cruciate ligament –  Posterior cruciate ligament –  Medial meniscus (semilunar car3lage) –  Lateral meniscus Synovial Joints: Knee – Interior Suppor3ng Structures Figure 8.8b Knee – Posterior Superficial View •  Adductor magnus tendon •  Ar3cular capsule •  Oblique popliteal ligament •  Arcuate popliteal ligament •  Semimembranosus tendon Figure 8.8e 31 11/07/12 The Elbow Joint •  A stable hinge joint that allows flexion/
extension only •  Ar3cula3ons between humerus -­‐ radius, humerus – ulna •  Biceps brachii muscle: –  abached to radial tuberosity –  controls elbow mo3on Ar3cula3ons of the Elbow •  Humeroulnar joint: –  larger ar3cula3on –  trochlea of humerus and trochlear notch of ulna –  limited movement •  Humeroradial joint: –  smaller ar3cula3on –  capitulum of humerus and head of radius Synovial Joints: Elbow •  Annular ligament •  Ulnar collateral ligament •  Radial collateral ligament Figure 8.10a 32 11/07/12 Synovial Joints: Elbow Figure 8.10b Elbow Figure 9–10
Injuries: Sprains and Strains Sprain: ligaments with torn collagen fibers –  Par3ally torn ligaments slowly repair themselves –  Completely torn ligaments require prompt surgical repair Strain: Muscles with torn fibers, also called “pulling a muscle” 33 11/07/12 Injuries: disloca3ons •  Disloca3on (luxa3on): –  ar3cula3ng surfaces forced out of posi3on –  damages ar3cular car3lage, ligaments (sprains), joint capsule •  Subluxa3on: –  a par3al disloca3on Car3lage Injuries •  The snap and pop of overstressed car3lage •  Common aerobics injury •  Repaired with arthroscopic surgery (ques3onable effec3veness Inflammatory and Degenera3ve Condi3ons •  Bursi3s –  An inflamma3on of a bursa, usually caused by a blow or fric3on –  Symptoms are pain and swelling –  Treated with an3-­‐inflammatory drugs; excessive fluid may be aspirated •  Tendoni3s –  Inflamma3on of tendon sheaths (which are enlarged bursa) typically caused by overuse –  Symptoms and treatment are similar to bursi3s 34 11/07/12 Arthri3s •  All forms of rheuma3sm that damage ar3cular car3lages of synovial joints •  More than 100 different types of inflammatory or degenera3ve diseases that damage the joints •  Most widespread crippling disease in the U.S. •  Symptoms – pain, s3ffness, and swelling of a joint Osteoarthri3s •  Caused by wear and tear of joint surfaces, or gene3c factors affec3ng collagen forma3on •  Affects women more than men •  85% of all Americans develop OA •  Generally in people over age 60 •  The exposed bone ends thicken, enlarge, form bone spurs, and restrict movement •  Joints most affected are the cervical and lumbar spine, fingers, knuckles, knees, and hips •  Treatments include glucosamine sulfate and CSPG to decreases pain and inflamma3on Rheumatoid Arthri3s •  Chronic, inflammatory, autoimmune disease of unknown cause I •  Involves the immune system •  Usually arises between the ages of 40 to 50, but may occur at any age •  Signs and symptoms include joint tenderness, anemia, osteoporosis, muscle atrophy, and cardiovascular problems –  The course of RA is marked with exacerba3ons and remissions •  Treatments include Enbrel, Remicade, Humira, methotreaxate 35 11/07/12 Developmental Aspects of Joints •  By embryonic week 8, synovial joints resemble adult joints •  Few problems occur un3l late middle age •  Advancing years take their toll on joints: –  Ligaments and tendons shorten and weaken –  Intervertebral discs become more likely to herniate –  Most people in their 70s have some degree of OA Summary • 
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Joint classifica3ons: structural and func3onal Types of joints by func3onal classifica3on Synovial joint detail Movements at synovial joints Classifica3on of synovial joints by shape Examples of joints Injuries Arthri3s 36